Study of the Voltage Behavior of Jointless Superconducting 2G Loops During Pulse Magnetization

Cruz, Vagner Santos da; Telles, Guilherme; Santos, Bárbara Maria Oliveira; Ferreira, A.C.; Andrade, R. de

doi:10.1109/tasc.2020.2968919

Cited by 11 publications

(4 citation statements)

References 14 publications

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“…Due to the different time scales in different damping rates, figure 11(b) is plotted using a normalised time scale. To understand how the ramping rate affects the trapped field, according to Faraday's Law [22], we have: here L is the inductance, j is the total flux, i(t) is the induced current, V 0 =E 0 l, E 0 =1 μV cm −1 as the criterion for measuring I c , l is the length of the ring, and n is the EJ power law index. When the changing rate is very slow as it is in the FC experiment, the heat dissipation inside the sample holder is small, so the temperature inside the ring remains constant, as well as the I c of the HTS rings.…”

Section: Modelling and Physics Discussionmentioning

confidence: 99%

4.6 T generated by a high-temperature superconducting ring magnet

Ali¹,

Zheng²,

Huber³

et al. 2020

Supercond. Sci. Technol.

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We report here a record 4.6 T trapped field generated by high temperature superconducting (HTS) persistent current loops using a HTS ring structure. By stacking 200 HTS rings into a compact magnet 90 mm in diameter, we performed a field cooling magnetisation at 25 K. The main advantage of the new magnet compared to existing trapped field HTS magnets is that the magnetic field is in the parallel direction to the ab plane of the HTS, leading to higher critical currents in the same magnetic field. Therefore, compact HTS magnets can be developed based on this principle to achieve high magnetic fields. Experimental results show that the final trapped field distribution depends on the ring geometry. We developed a new three dimensional model to simulate the magnetic field distribution within the HTS ring magnet and good agreement between experiments and simulation have been found. The temperature dependency and ramping rate dependency have been studied numerically as potential factors to influence the magnet field. The proposed HTS ring magnet will have promising applications in medical imaging devices, e.g. MRI, as well as electrical machines.

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Section: Modelling and Physics Discussionmentioning

confidence: 99%

4.6 T generated by a high-temperature superconducting ring magnet

Ali¹,

Zheng²,

Huber³

et al. 2020

Supercond. Sci. Technol.

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“…Taking i(t 4 ) as the input of the second pulse magnetization, the current from t 5 to t 8 could be calculated through (17). Comparing i(t 4 ) and i(t 8 ), it can be found that the reverse current would increase with the accumulation of pulse magnetization.…”

Section: Numerical Analysis Of Cumulative Effectmentioning

confidence: 99%

“…Magnetization mechanisms and the structural optimization of ring-shaped magnets have been systematically investigated through numerical models and experiments. C. Rong et al and D. Qiu et al studied the characteristics of the trapped magnetic field, including relaxation of persistent current and magnetic field stability [15,16], while Vagner Santos da Cruz et al discussed the voltage behavior of the ring-shaped magnet, classifying different magnetization stages by the magnitude of the induced current [17]. Jie Sheng et al preliminarily introduced the cumulative effect of the trapped field under multi-pulse magnetization as well as the trapped field under demagnetization [18], and then proposed a hybrid magnet, which combines HTS stack tapes and a ring-shaped magnet to elevate the trapped field [19].…”

Section: Introductionmentioning

confidence: 99%

Study on the Electromagnetic Characteristics of Ring-Shaped Superconducting Permanent Magnets for Medical Applications

et al. 2022

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The ring-shaped superconducting permanent magnet, with its great advantages in flexible sizing and trapped field, has become a potential candidate for portable medical applications. However, due to the complex geometry involved, it is difficult to predict its electromagnetic performance by traditional numerical methods. This paper presents a field-circuit coupling method to study the entire magnetization process of the ring-shaped magnet. Firstly, the principle of the numerical method is introduced and it is proved to be sufficient for a ring-shaped magnet with a large turn number. Then, the numerical model is used to discuss the relationship between pulse waveform and magnitude of trapped field. Next, the accumulation effect under multi-pulse magnetization is theoretically analyzed and proved by both experiments and simulation. Finally, based on the numerical model, a study on the decay process of ring-shaped magnets is also presented. Conclusions from this paper will be helpful for obtaining the optimization strategy of magnetization of ring-shaped magnets for practical medical applications.

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“…When a superconducting loop is placed in a changing applied field and the current of the tape is below its critical current, it induces a compensating current inside the loop. Therefore, equation ( 1) is used to describe the relationship between the change of total magnetic flux inside the ring and the induced current according to Faraday's law, [17,18]…”

Section: Excitation Processmentioning

confidence: 99%

Induced current of high temperature superconducting loops by combination of exciting coil and thermal switch

Wang¹,

Wang²,

Chai³

et al. 2022

Chinese Phys. B

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With its commercialization, the second-generation (2G) high temperature superconducting (HTS) RE–Ba–Cu–O (REBCO, RE is rare earth) tape is extensively applied to the superconducting magnets in the high magnetic fields. However, unlike low temperature superconducting (LTS) magnets, the HTS magnet cannot operate in the persistent current mode (PCM) due to the immature superconducting soldering technique. In this paper, an exciting method for two HTS sub-loops, so-called charging and load loops, is proposed by flux pump consisting of exciting coil and controllable thermal switch. Two HTS sub-loops are made of an REBCO tape with two slits. An exciting coil with iron core is located in one sub-loop and is supplied with a triangular waveform current so that magnetic field is generated in another sub-loop. The influence of magnetic flux on induced current in load loop is presented and verified in experiment at 77 K. The relationship between the induced magnetic flux density and the current on the sub-loops having been calibrated, magnetic flux density, and induced current are obtained. The results show that the HTS sub-loops can be excited by a coil with thermal switch and the induced current increases with magnetic flux of exciting coil increasing, which is promising for persistent current operation mode of HTS magnets.

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Study of the Voltage Behavior of Jointless Superconducting 2G Loops During Pulse Magnetization

Cited by 11 publications

References 14 publications

4.6 T generated by a high-temperature superconducting ring magnet

4.6 T generated by a high-temperature superconducting ring magnet

Study on the Electromagnetic Characteristics of Ring-Shaped Superconducting Permanent Magnets for Medical Applications

Induced current of high temperature superconducting loops by combination of exciting coil and thermal switch

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